Bruce J. Hillman

Factors influencing radiologists to choose research careers.

The future of radiology is threatened by the paucity of competent researchers who are radiologists. To determine what influences are most important in selecting and training potential radiology researchers, we conducted a survey of 5000 practicing radiologists, including all members of the Association of University Radiologists. We also surveyed 3000 randomly selected radiology trainees. A research career was empirically defined as 20% or more of a radiologists time being involved with research. Response to the practicing radiologists and radiology trainees surveys was 28% and 19%, respectively. Radiologists who attended medical school or trained in radiology at an institution among the top 20 for research funding more frequently chose careers in research than those who matriculated and trained elsewhere. Publishing at least one research article, having a dedicated radiology research fellowship, having access to grant funds, and using computers during medical school or radiology training were factors typifying radiologists who chose research careers. Research radiologists were more concerned about the value of performing research and less concerned about personal income than those choosing careers not focusing on research. These results suggest that it might be possible to select radiology trainees who are more likely to become researchers based on their backgrounds and attitudes. An appropriate milieu during training enhances the likelihood of radiologists choosing research careers.

Improving Diagnostic Accuracy: A Comparison of Interactive and Delphi Consultations

Consultation among physicians on difficult diagnostic problems is commonly used to improve the accuracy of medical decisions. Such consultation is most often informal and interactive. Nevertheless, behavioral studies suggest that non-interactive techniques may be more effective problem solving methods. Of these the Delphi approach, involving pooling and feedback of anonymously contributed information, has generated particular interest. To assess the relative effectiveness of independent decision making, interactive group consultation, and Delphi techniques in a clinical setting we compared the diagnostic accuracy of 17 radiologists interpreting radiologic examinations in these settings. Interactive consultation improved performance by 69% compared to radiologists interpreting the studies individually. In addition, two Delphi strategies each produced an additional 20% mean improvement in accuracy over interactive consultation. Whereas interactive consultation improved the accuracy of the best individual readers by only 6%, a Delphi model improved their performance by 25%. Thus, Delphi was an effective, easily applied method of clinical consultation whose usefulness in other clinical setting should be evaluated.

Mammogram interpretation by physician assistants

The objective of this study was to determine whether a health maintenance organization (HMO) desirous of providing low-cost, quality mammography could employ physician assistants (PAs) to interpret mammograms under the supervision of HMO radiologists. After intensive training in mammographic interpretation, four PAs individually interpreted 727 mammograms of 470 normal breasts, 75 breasts with benign breast masses, and 182 breasts with cancer. The interpretations by the PAs were more sensitive and as specific as those made by six HMO radiologists who interpreted the same cases, and as effective as those by radiologists described in the literature. In receiver-operating-characteristic curve analysis, the areas under curves for PAs were larger than those under curves for radiologists. Interpretations by PAs took less time and cost less than did those by radiologists; the dispositions recommended by PAs were similar to those recommended by radiologists. We conclude that properly trained, evaluated, and supervised PAs can interpret mammograms. Legal, practical, and ethical considerations dictate that this can best be accomplished under the direction of radiologists who are well trained in mammography.

Microvascular changes in rabbit kidneys after extracorporeal shock wave treatment.

Concerns about the safety of extracorporeal shock wave lithotripsy include the risk of vascular damage and the genesis of hypertension. We evaluated gross specimens and barium microangiograms of the right kidneys of 14 rabbits exposed to shock waves; the untreated left kidneys served as controls. Six rabbits were assessed immediately after shock wave treatment, whereas the other eight rabbits had the same procedure 3 months later. All six acute phase animals showed microangiographic changes indicative of shock wave trauma, including cortical, subcapsular, and medullary extravasation of barium and patchy loss of efferent vessels. No significant vascular abnormalities were seen in the control kidneys. All kidneys treated from the animals that had delayed microangiography showed macroscopic evidence of fibrotic capsular thickening and parenchymal scarring. Microscopically, there was crowding of glomeruli and areas of avascularity. In this model, shock waves damaged the cortical circulation and resulted in persistent alterations of the microvasculature that potentially could be responsible for the abnormal secretion of renin.

CT determination of renal and hepatic microvascular volumes in experimental acute renal failure.

Alterations in renal blood flow are considered to play an important role in the pathogenesis of acute renal failure. Most techniques designed to assess organ blood flow and microcirculatory disturbances are relatively invasive and cumbersome. This study describes a noninvasive method for the determination of an organs fractional vascular volume (FVV)-the fraction of an organ occupied by blood vessel lumen. It utilizes computed tomographic (CT) scanning and a contrast agent, perfluoroctylbromide (PFOB), which remains intravascular and is not excreted by the kidney. Acute renal failure (ARF) was induced in rats by intraperitoneal injection of glycerol (5 g/kg). CT scans of kidneys, liver, and heart were performed prior to and following intravenous administration of PFOB. FVV of kidney and liver were calculated prior to induction of ARF and at selected time periods following ARF (20-50 minutes and 60-120 minutes). FVV of the kidney decreased significantly 20-50 minutes following ARF and had returned to control values at 60-120 minutes. Renal histologic abnormalities were more severe at the later time period. Thus, early alterations in blood flow precede pathologic abnormalities in the kidney following glycerol-induced ARF. Determination of an organs fractional vascular volume is a simple noninvasive technique which provides useful information on the microcirculation during the course of experimental disease.

Research and research training in academic radiology departments. A survey of department chairmen.

We surveyed 121 chairmen of academic radiology departments to assess how these departments select and educate their residents and fellows in research. Eighty-six chairmen responded (71%). The majority of their programs select at least some of their trainees for their potential as researchers and nearly all encourage trainees to perform research. The more the selection process focuses on research, the greater the percentage of residents and fellows that participate in research during training. Nonetheless, only about one-third of residents and half of the fellows perform and publish research. Only half the programs offer formal research seminars and few trainees opt for additional research training. These results may relate to the relatively small percentage of faculty performing prospective clinical and laboratory research. These findings are disappointing in the light of previous results suggesting that performing research, publication, and formal research education during training correlate highly with the development of successful research careers. Chairmen could increase the likelihood of trainees choosing research careers and being successful in publishing research by providing early exposure to research experiences and providing formalized research training.

CLINICAL EXPERIENCE IN THE USE OF PHOTOSTIMULABLE PHOSPHOR RADIOGRAPHIC SYSTEMS

The experience with CR systems gained at the three institutions described in this report demonstrates numerous advantages over the conventional screen-film system. These include: (1) a reduction in the radiation exposure delivered to the patient (25% to 50%); (2) a decrease in the number of repeat examinations needed, especially in portable units where technical difficulties are common with screen-film examinations; this is attributable to the linear, wider dynamic range of CR systems compared with screen-film combinations; (3) the capability to archive electronically all images by means of a digital optical storage system; (4) automatic electronic setting of the laser scanner for the latitude and sensitivity on each image; (5) the digital images are available for transmission to all image display workstations on a local or wide-area network; and (6) the ability to adjust interactively the display parameters to best depict images and pathology as well as salvage technically suboptimal examinations. Several disadvantages of CR systems compared with conventional screen-film examinations have also been identified.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical assessment of phosphor-plate computed radiography: equipment, strategy, and methods.

Initial experiences with a medical innovation project promise future applicability. Scientific assessment of the innovation usually points out deficiencies that must be overcome before optimal, widespread use of the technology is feasible. This presentation details the equipment, strategy, and methodological principles used at the University of Arizona in assessing the clinical use of computed radiography based on using phosphor plates as the X-ray receptor. The focus of this research has been to evaluate the applicability of computed radiography to clinical indications which might test potential weaknesses or virtues of the technology. We present examples of experiments that illustrate the general principles described.

The diffusion of magnetic resonance imaging scanners in a changing U.S. health care environment

Technological aspects and early clinical experiences are arousing great enthusiasm over magnetic resonance imaging (MRI). However, influences such as regulation, reimbursement, and increasing competition also are playing important roles in determining the diffusion of this new technology. Of these considerations, competition among providers seems the most important. Competition related to MRI is manifested as direct competition over MRI services, using MRI to improve a providers strategic position and competition among specialties. In making decisions concerning MRI acquisition and operation, providers are drawing upon their experiences with computed tomography (CT) to help them determine when would be the best time for acquisition, how to decide whether acquisition is appropriate, and how best to acquire, operate, and market the technology.

The Effects of Diltiazem and Captopril on Glycerol-Induced Acute Renal Failure in the Rat: Functional, Pathologic, and Microangiographic Studies

To evaluate the effects of pharmacologic vasodilatation on glycerol-induced acute renal failure, we studied untreated animals and those given Captopril and Diltiazem at periods ranging from 30 minutes to four weeks after the onset of acute renal failure. At each time frame, comparative coded assessments of renal function, histology, and microangiography were performed. Diltiazem, a calcium channel blocker, significantly reduced the severity of the renal failure, decreased the extent of tubular cell necrosis, and was associated with a more rapid histologic and functional recovery. Captopril, an angiotensin converting enzyme inhibitor, did not influence renal function or pathology throughout the four-week observation period. Microangiography revealed marked differences among the experimental groups. Most notably, there was better visualization of the microvasculature in Diltiazem-treated kidneys at one and two weeks. However, at four weeks, all groups showed similar, severe microangiographic abnormalities. Diltiazem offers significant protection against glycerol-induced acute renal failure in rats. Its mechanism of action in this context remains unknown. Renal function and pathology do not correlate well with microangiographic perfusion patterns in this model of acute renal failure.